1. Field of the Invention
This invention relates to an information processing system adapted to be used for a computer output microfilmer (COM) which records a computer output on a recording medium such as a microfilm, and more particularly to an information processing system for a COM device in which two kinds of information processing devices are used for simultaneously processing main information and sub-information in parallel.
2. Description of the Prior Art
Recently, a computer output microfilmer (hereinafter referred to as "COM device") has been developed and used as a new output device for an electronic computer. The COM device reads out the output data of a computer, processes the data and records the processed output data directly on a microfilm. The COM device is advantageous for its high speed in recording information.
In the COM device, it is necessary that not only the main information but also the sub-information such as titles or indices should be recorded so that the main information may be recorded together with such sub-information.
In the conventional COM devices, there have been two methods for recording the sub-information together with the main information. In one of them, the sub-information is prepared by a separate computer and is stored in a magnetic tape or the like outside the COM device so that the sub-information is recorded on a microfilm together with the main information by the COM device. In this case, the separate computer is over-loaded and the throughput time becomes long. Further, in this case, the operation of the COM device and the computer is complicated. In the other method, a mini-computer is incorporated in the COM device for automatically preparing the sub-information in the COM device based on the key words obtained from the main information read out from a magnetic tape or the like, thereby recording the sub-information together with the main information. This method is widely used in the so-called intelligent COM devices which are widely available in the recent market. In this method, however, the main information and the sub-information are processed in series, and accordingly, the processing speed is low and the throughput time is long. If a high speed processing device is incorporated to increase the speed, the cost of the COM device is increased. A prior art system wherein a mini-computer is employed is a 3800 COM System Overview manufactured by the Bell & Howell Co., U.S.A. It is desirable in a COM device that the information be processed and recorded at a high rate of speed. In particular, in a COM device of the type which produces sub-information based on the main information inputted thereinto, the information processing should occur at a high rate of speed. The present invention makes an improvement in this type of COM device.
For high speed processing, a high speed mini-computer (e.g. PDP/8 or PDP/11 produced by Digital Equipment Corporation in the U.S.A., or MCR 605) is incorporated in the conventional COM device. However, since a high speed mini-computer such as the PDP/11 is very expensive, the price of a COM device containing such a mini-computer is very high.
On the other hand, micro-computers have been used in other fields such as the 8080 micro-computer produced by INTEL in the U.S.A. or Z/80 micro-computer produced by Zilog in the U.S.A., these micro-computers being much less expensive than a mini-computer. The 8080 or Z/80 micro-computers including interfaces therefor are approximately ten times less expensive than the above-mentioned PDP/11 mini-computers. If a micro-computer could be used as an information processing device for a COM device, the cost of the COM device would be substantially reduced. However, the data processing speed of a micro-computer is very low. The data processing speed of a micro-computer is generally 1/2 to 1/3 that of a 16 bit parallel processing type mini-computer. Accordingly, a micro-computer has not been used in conventional COM devices.
In view of the foregoing, this invention has an object to provide a COM device equipped with micro-computers having a short throughput time. The term "short throughput time " means that the throughput time of the COM device with micro-computers according to this invention is the same as or shorter than the throughput time of a conventional COM device with a mini-computer.
The assignee of this application has manufactured a commercially available COM device using the information processing system including micro-computers according to this invention. The inventor conducted a performance test of this COM device, and as a result, found that the recording speed of this COM device was higher than a conventional COM device (that is, the aforementioned 3800 COM system).